41 Arae 2

41 Arae A is a yellow-orange to orange-red
star that is dimmer than our Sun, Sol.
(See a Digitized Sky Survey
field
image of
41 Arae from the
Nearby
Stars Database.)

System Summary

This binary system is located only
about 28.7 light-years (ly) away our Sun, Sol. It lies in the north
central part (17:19:63.84-46:38:10.44, ICRS 2000.0) of Constellation
Ara, the Altar --
north of Alpha Arae. While smaller and cooler than Sol, 41 Arae A is
somewhat more like a sister star than nearby
Epsilon Eridani.

The star is a main sequence, yellow-orange dwarf (G8-K0 V).
It has about 58 percent of Sol's diameter and around 42 percent
of its luminosity. The star does not appear to be as enriched
as Sol in elements heavier than hydrogen ("metals") because it
has only 45 percent of Sol's abundance of iron
(Cayrel
de Strobel et al, 1991, page 301). Thus, 41 Arae A may be a
relatively old star. In addition to Star B, 41 Arae A may also
have two optical companions. Some useful star catalogue numbers
for 41 Arae A are: 41 Ara, HR 6416, Gl 666 A, Hip 84720,
HD 156274, CD-46 11370, CP(D)-46 8513, SAO 227816, BSO 13 A,
LHS 444, LTT 6886, LPM 636, LFT 1334, and Brs 13.

The new
Sixth Catalog of
Orbits of Visual Binaries provides two very old estimates of
orbital elements for 41 Arae A and its companion. According to
Roland
Wielen (1962; see Brs 13 on page 603), who used a computer to
mathematically iterate (photographic observations in both
coordinates and visual observations of the position angle) to
"best fit" estimates, AB travel in an extremely eccentric orbit
(e= 0.901) that takes 2,200 years to complete, with a semi-major
axis of 210 AUs (23.900", using HIPPARCOS parallax of 0.11381
+/- 0.00136") when viewed at an inclination of 44.88° from the
perspective of Earth. On the other hand, N. Wieth-Knudsen
(Inf. Circ. 13, 1957) found that the orbit of the AB pair took
only 693 years to complete, given a semi-major axis of 91.5 AUs
(10.415", same parallax), an eccentricity of 0.779, and an
inclination of 35.64°. Wieth-Knudsen's estimates were used in
Poveda
et al (1994, pages 32 to 33). (See an
animation of the orbits of Stars A
and B and their potentially habitable zones, with a table of
basic orbital and physical characteristics.)

Up-to-date technical summaries on this star can be found at:
the Astronomiches Rechen-Institut at Heidelberg's
ARICNS,
the
Near
Stars Database, and the Research Consortium on Nearby Stars
(RECONS).
Additional information may be available at Roger Wilcox's
Internet Stellar Database.

Constellation Ara, the Altar, is located next to the celestial south pole.
Ara is another of those constellations created by the Abbé [Abbot]
Nicholas
Louis de La Caille (1713-1762), who had the great honor of naming
15 of the 88 constellations by becoming the first astronomer to
systematically observe the entire night sky by traveling to the Cape of
Good Hope at the southern tip of Africa from 1750-54.
For more information on stars and other objects in this Constellation
and an illustration, go to Christine Kronberg's
Ara.
For another illustration, see David Haworth's
Ara.

For more information about stars including spectral and luminosity
class codes, go to ChView's webpage on
The Stars of
the Milky Way.